GENERAL CERTIFICATE OF SECONDARY EDUCATION
A451
COMPUTING
Computer Systems and Programming
* O C E / 2 6 5 7 1 *
Candidates answer on the question paper.
OCR supplied materials:
None
Tuesday 11 January 2011
Afternoon
Duration: 1 hour 30 minutes
Other materials required:
None
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INSTRUCTIONS TO CANDIDATES
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Write your name, centre number and candidate number in the boxes above. Please write
clearly and in capital letters.
Use black ink. Pencil may be used for graphs and diagrams only.
Read each question carefully. Make sure you know what you have to do before starting
your answer.
Write your answer to each question in the space provided. Additional paper may be
used if necessary but you must clearly show your candidate number, centre number and
question number(s).
Answer all the questions.
Do not write in the bar codes.
INFORMATION FOR CANDIDATES
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The number of marks is given in brackets [ ] at the end of each question or part
question.
The total number of marks for this paper is 80.
Your Quality of Written Communication is assessed in questions marked with an
asterisk (*).
This document consists of 16 pages. Any blank pages are indicated.
© OCR 2011 [F/600/2375]
DC (KN/CGW) 26571/3
OCR is an exempt Charity
Turn over
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1
Jo buys a notebook computer which has a 3MHz quad-core central processing unit (CPU).
(a) State the purpose of the CPU.
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(b) Describe what is meant by
3MHz CPU
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quad-core CPU
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© OCR 2011
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2
A small business has three stand-alone computers, a printer and an internet connection in an
office.
(a) State two advantages of connecting the computers to create a local area network.
1
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2
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(b) Describe, using a diagram, how the computers can be connected to each other using a bus
topology, stating what hardware will be needed.
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© OCR 2011
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3
(a) Calculate the denary value of the 8-bit binary number 10010111.
You must show your working.
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[2]
(b) Add the following two 8-bit binary numbers and explain the result.
You must show your working.
+
1
0
0
1
0
1
1
1
1
1
0
1
1
0
0
0
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© OCR 2011
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4
A desk-top computer’s memory includes ROM and RAM.
Tick one box in each row to show whether each of the statements is true for ROM or RAM.
ROM
RAM
Programs and data which are
currently in use are loaded here.
All the contents are lost when the
power is turned off.
It is used to boot up the computer
when it is switched on.
[3]
© OCR 2011
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5
Karen wants to use handheld computers to take customers’ orders in her restaurant. She is thinking
of using custom written, open source software.
(a) State what is meant by custom written software.
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(b) State two reasons why Karen may decide to use custom written software.
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2. ...............................................................................................................................................
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(c)* Discuss the implications of creating open source software for the restaurant.
The quality of written communication will be assessed in your answer to this question.
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© OCR 2011
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6
A shopping centre uses several remote-controlled CCTV cameras for security. An operator uses a
computer to watch, control and record the output of the cameras.
State an input, output and storage device which will be needed by the computer. For each, explain
the reason why it is needed.
Input device
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Reason
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Output device:
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Reason
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Storage device:
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Reason
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© OCR 2011
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7
A teacher uses a database to store the marks of pupils from all year 9 classes.
(a) PUPIL and CLASS are two entities used in this database.
Explain the term entity.
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(b) The data for the first four pupils in the PUPIL table is shown below.
(i)
PupilNumber Surname
FirstName
ClassCode
A01
Adams
Michelle
9DK
A02
Ali
Mohammed
9BH
A03
Ali
Shirelle
9DK
A04
Azor
Michelle
9FT
State the primary key for the PUPIL table and explain your answer.
Primary Key .................................................................................................................. [1]
Explanation
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(ii)
The database also contains a CLASS table. The primary key for the CLASS table is
ClassCode.
Explain why ClassCode has also been included in the PUPIL table.
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© OCR 2011
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A syntax error can occur when writing a program.
(a) State what is meant by a syntax error, giving an example.
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(b) Describe tools and facilities available in an integrated development environment (IDE) which
can help the programmer to identify and correct syntax errors.
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© OCR 2011
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9*
Computer technology has changed the ways in which teenagers interact with each other.
Explain how developments in software and hardware have enabled new methods of communication
among teenagers.
The quality of written communication will be assessed in your answer to this question.
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© OCR 2011
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10 (a) Explain how ASCII is used to represent text in a computer system.
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(b) State what is meant by the character set of a computer.
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(c) Unicode is also used to represent text in a computer system.
Explain the difference between the character sets of Unicode and ASCII.
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PLEASE TURN OVER FOR THE NEXT QUESTION
© OCR 2011
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11 Frances is writing a program which simulates a dice game played with three ordinary 6-sided
dice.
(a) When the player rolls the three dice, the player is given points according to the algorithm
expressed in the flow diagram below.
BEGIN
YES
Are all three
dice equal?
Score = total on the 3
dice
YES
NO
Are two of the
dice equal?
Score = sum on the 2 equal dice
NO
Score = 0
Score = Score – (the number on
the other dice)
END
State the value of the score if the dice rolled are
345
Score : .........................
444
Score : .........................
556
Score : .........................
[3]
© OCR 2011
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(b) Some rolls of the dice result in a negative score.
State a set of three numbers which can be used to test whether the algorithm produces a
negative score when it should, and state the expected output for your test data.
Set of test data: .........................................................................................................................
Expected output: .................................................................................................................. [2]
When the dice are rolled, the results are stored in an array called DiceResult.
For example, if the first dice shows a 5 then the value of DiceResult(1) becomes 5.
(c) Describe what is meant by an array.
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(d) State the data type and size of the array DiceResult giving a reason for each.
Data type of DiceResult: ...........................................................................................................
Reason: ....................................................................................................................................
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Size of array DiceResult: ..........................................................................................................
Reason: ....................................................................................................................................
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PLEASE TURN OVER FOR THE LAST QUESTION
© OCR 2011
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14
(e) The routine for rolling the dice is written as a sequence below.
BEGIN RollTheDice
DiceResult(1) = Random Number between 1 and 6
DiceResult(2) = Random Number between 1 and 6
DiceResult(3) = Random Number between 1 and 6
END
Rewrite this routine so that it uses iteration.
You may use a diagram.
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[END]
© OCR 2011
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© OCR 2011
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